This invention relates to the treatment of fractures, and it relates especially, though not exclusively, to apparatus for effecting such treatments as are applicable to fractures of long bones such as the humerus.
A well established and highly successful procedure used in the treatment of long bone fractures involves the use of intramedullary nails which are inserted substantially axially of a bone and to one side of the fracture, and extend through the medullary cavity (reamed out if necessary) and past the region of fracture to an area of sound bone. The proximal end of such a nail is secured to the bone at or adjacent to the region of its entry into the bone, whereas the distal end of the nail has to be secured to the sound bone beyond the fracture. One difficulty associated with this procedure is the accurate location of the nail and its fixing points with which separate securing members, such as transversely inserted fixing devices, e.g. screws, need to engage.
It has previously been proposed to use radiographic techniques to assist the surgeon in this respect, but it is preferable to avoid subjecting a patient to radiation for such purposes, and accordingly various mechanical procedures have been developed in recent years. Such procedures typically involve the use of jigs which are attachable to the nail during the surgical alignment process and which provide predictive guidance as to the location of the nail (particularly the distal end thereof), thereby to ease the difficulty described above.
Alignment procedures of this general kind are described in GB 2 288 738 A; GB 2 258 154 A; WO 96/03085 A1; U.S. Pat. No. 5,352,228 and U.S. Pat. No. 4,913,137 and it is an object of this invention to provide improved apparatus and methods for the application, alignment and/or engagement of transverse fixing devices with intramedullary nails, and/or to effect improved stability and/or mobility of fractured bones.
According to the invention in one aspect there is provided an apparatus for the treatment of bone fracture, comprising an elongate member for substantially axial insertion into the bone such that it spans the fracture; the elongate member being formed, adjacent one or both of its proximal and distal ends with a fixture location means, which may comprise an aperture which is intended to receive a fixing device inserted transversely of the elongate member and passing through part at least of the bone to be treated; the position of the fixture location and the line of insertion of the fixing device being defined by a jig temporarily affixed to the proximal end of the elongate member; characterised in that a guide means is passed through the fixture location and acts as a guide for the desired location of the fixing device, and drill means guided by the guide means, is used to form a bore communicating with the fixture location, said bore being adapted to accommodate the fixing device.
Preferably the guide means comprises a wire, such as a K-wire, and the drill means is axially apertured to accommodate said wire.
According to another aspect of the invention there is provided an apparatus for the treatment of bone fracture, comprising an elongate member for substantially axial insertion into the bone such that it spans the fracture, the elongate member being formed, adjacent at least its distal end with a fixture location intended to receive a fixing device inserted transversely of the elongate member and to engage with an aperture present in the elongate member so as to permit the elongate member to be drawn into intimate contact with the inner surface of cortical bone, thereby to enable the elongate member to act as a support member.
Preferably the fixing device is a screw and the fixture location comprises an internally threaded aperture formed in said elongate member.
Preferably the elongate member is formed with a plurality of further apertures adjacent the distal end thereof, any or all of which further apertures may be internally threaded.
Preferably, the elongate member comprises an intramedullary nail configured in the region thereof occupied by said aperture and possibly also said further apertures to permit its close conformity to the inner cortical wall of said bone.
Preferably also the proximal end of said elongate member also is formed with one or more apertures to accommodate transversely disposed fixing devices.
Where a plurality of said fixing devices is employed to cooperate with respective apertures adjacent the proximal end of said elongate member, said fixing devices are adapted to pass through the elongate member and into sound bone and are deployed in substantially parallel planes transverse to said elongate member, but are misaligned so as to respectively engage areas of bone more widely separated than the areas that would have been engaged by the fixing devices had they been disposed in alignment with one another.
In an alternative embodiment, an elongate member is adapted to be passed through a fixing device whereafter the fixing location of the proximal end of said elongate member resides in contact with the fixing device.
Conveniently, the said fixing device may comprise an aperture whereby said elongate member can pass through the fixing device in use.
According to a further aspect of the invention there is provided a method for the treatment of bone fracture, comprising the steps of:
inserting an elongate member formed adjacent one or both of its proximal and distal ends with a fixture location, said elongate member being insertable substantially axially into the bone such that it spans the fracture; the fixture location being adapted to receive a fixing device inserted transversely of the elongate member and passing through part at least of the bone to be treated;
defining, by means of a jig temporarily affixed to the proximal end of the elongate member, the position of the fixture location and the line of insertion of the fixing device;
utilising said jig to pass a guide means through the fixture location and along said line of insertion;
anchoring said guide means into sound bone; and
drilling, guided by the guide means, a bore communicating with the fixture location and adapted to accommodate the fixing device.
According to a still further aspect of the invention there is provided a method for the treatment of bone fracture, comprising the steps of:
forming adjacent at least the distal end of an elongate member, with a fixture location adapted to receive a fixing device inserted transversely of the elongate member and to engage with the aperture of the elongate member and inserting said elongate member substantially axially into the bone such that it spans the fracture; and
utilising the fixing device in cooperation with the fixture location formed in the elongate member to draw the elongate member into intimate contact with said bone.
A particular application of the invention relates to the treatment of four-part and other fractures of the surgical neck and shaft of the humerus.
Comminuted four-part fractures of the upper end of the humerus present particular difficulties in imparting a sufficient degree of stability to the repaired bone structure. In attempting to stabilise the structure, it is necessary to take into account the forces acting on the fracture fragments, such as the supraspinatus muscle and the other muscles of the rotator cuff which act on the main proximal fragment of the fracture through the greater and lesser tuberosities. Sometimes, moreover, the greater tuberosity is a separate fragment and is displaced by muscular pull. The lesser tuberosity may also be a separate fragment, which tends to follow the greater tuberosity fragment because of the close attachment of the rotator cuff muscles.
Secure fixing of the distal end of an intramedullary nail enables the latter to be used as an internal plate, stabilising the repaired structure.